Field of the Invention
This invention relates to an automatic sealing valve with a cylindrical inflation nozzle having a peripherally extending welding rim for welding it to that foil of an inflatable body through which the inflation nozzle extends.
Description of Prior Art
Various types of automatic sealing valves have been on the market for several years. In such conventional sealing valves, the automatic sealing effect is generated by a small lid pivotally disposed on the end of the inflation nozzle. This relatively small lid, which is positioned opposite the inflating side of the inflation nozzle and is constructed as one piece with the inflation nozzle being pressed on the inflation nozzle by the internal pressure of an inflated inflatable body. The force from pressure acting on the inflation nozzle is conventionally very small, because the area where pressure is effective only corresponds to the open cross-sectional area of the inflation nozzle. If the internal pressure within the inflatable body is not considerable, then the sealing effect of such a valve is completely insufficient. The internal pressure in inflatable bodies in particular, such as air mattresses, beach balls, swimming aids and the like, which are often inflated by a human exhaling into the device, is relatively low. As a result, authorities in several countries have not approved such conventional sealing valves.
Manufacturers of such conventional sealing valves have therefore provided them additionally with a plug which is inserted into the inflation nozzle.
Now, if the inflation nozzle is closed off with the plug, there is no pressure difference between the two sides of the small lid and its closure effect is eliminated. Only if pressure is exerted on the inflatable body which increases the interior pressure can the small lid be forced against the inflation nozzle. As a result, the pressure on the plug is decreased. Thus the small lid only acts as protection for preventing increased pressure on the plug.
An automatic sealing valve for inflatable bodies which is completely made of foil is known from U.S. Pat. No. 4,674,532. A sack-like body, which is open towards the inside of the inflatable body, is welded between two flat foils which perpendicularly extend through the foil of the inflatable body.
The intention is to inflate this sack-like body with the internal pressure in the inflatable body and thus to plug and seal the free cross section between the two foil strips, which are welded together along their long sides. Here, too, the effective forces are very small and the sealing effect is thus minimal.